Pivot Hood Assembly

ABSTRACT

A pivot hood assembly ( 12 ) comprises a pair of identical hood pieces ( 14, 16 ) comprising a shell ( 20, 22 ) and a supporting frame assembly ( 24, 26 ). Each hood piece is attachable to a ventilation shaft ( 18 ) by an attachment framework ( 32 ) to which the hood pieces are pivotably attached. The hood pieces pivot between a closed position where inner edges ( 52 ) of each hood piece contact each other, and an open position where the inner edges ( 52 ) are spaced from each other to form an opening where the ventilation shaft is accessible.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. application Ser. No.60/593,304 filed Jan. 5, 2005, and U.S. application Ser. No. 60/593,384filed Jan. 10, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to hood assemblies for roof-mountedventilation shafts. In one embodiment, the invention relates to apivoting hood assembly. In another embodiment, the invention relates toa two-piece pivoting hood assembly.

2. Description of the Related Art

Ventilation shafts are ubiquitous for providing fresh air to theinterior of large commercial and industrial buildings, and forexhausting air from the interior of such buildings. Ventilation shaftsare typically mounted to extend vertically upwardly through the roof ofthe building, and may be several feet in width in order to providesufficient airflow. A motorized fan assembly is frequently installed inthe ventilation shaft to increase the flow of air through the shaft.These ventilation shafts are typically provided with a hood extendingover the shaft to prevent the influx of precipitation, debris, animals,and the like.

Ventilation shaft hoods are typically adapted to be removed from theventilation shaft to provide access to the shaft for cleaning,maintenance, removal of obstructions, and the like, particularly with amotorized fan assembly installed in the shaft. However, ventilationshaft hoods are typically very large due to the size of the ventilationshaft, heavy, and unwieldy, making them difficult to remove from theventilation shaft. Hoods have been adapted to be pivoted about an axisextending along one edge of the ventilation shaft. However, such hoodstypically require more than one person to lift and pivot the hood awayfrom the ventilation shaft.

Other hoods are fabricated as two identical mating pieces which can bemoved away from the ventilation shaft by sliding the hood pieceshorizontally along a track assembly. However, the track assembly is acomplex mechanism, involving significant cost in its fabrication.Nevertheless, it can be difficult to move the hood pieces if the trackassembly becomes misaligned, corroded or otherwise encrusted withdebris.

Ventilation shaft hoods are typically fabricated off-site and must bedelivered to the site where they are to be installed. Due to their sizeand weight, transportation must typically be done on a large semitractor-trailer, which can be costly.

SUMMARY OF THE INVENTION

According to the invention, a pivot hood assembly for a ventilationshaft, comprises a pair of hood pieces, each hood piece having a shellwith an inner edge, and a supporting frame assembly; and an attachmentframework adapted to be securely fixed to a ventilation shaft. Each hoodpiece is pivotably mounted to the attachment framework for movementbetween a closed position where the inner edges contact each other andan open position where the inner edges are spaced from each other toform an opening. In this way, when the attachment framework is fixed toa ventilation shaft and the hood pieces are pivoted to the closedposition, the pivot hood assembly is configured to control the flow ofair entering or exiting the ventilation shaft, and when the hood piecesare pivoted to the open position, the ventilation shaft is accessiblethrough the opening.

Preferably, each hood piece is pivotably mounted to the attachmentframework at a balanced pivot point wherein little force is required tourge the hood piece to pivot. Also, each pivot hood preferably has atleast one closure device to secure the inner edges to each other whenthe hood pieces are in the closed position.

In one aspect of the invention, the pivot hoods are cooperatively linkedso that movement of one pivot hood will also move the other pivot hood.At least one motor can be used to move the pivot hoods between the openand closed positions.

Typically, the pivot hood assembly can have an air filter in each pivothood and/or a screen in each pivot hood. Preferably, the pivot hoodassembly is mounted to a ventilation shaft with the attachment frameworkattached to the ventilation shaft at an upper end thereof so that whenthe pivot hoods are in the closed position, each pivot hood has aportion extending below the ventilation shaft end.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a hooded ventilation system according tothe invention comprising a pivot hood assembly mounted to a ventilationshaft.

FIG. 2 is a perspective view of the pivot hood assembly illustrated inFIG. 1 comprising a pair of pivot hoods pivotally attached to theventilation shaft.

FIG. 3 is an exploded view of the hooded ventilation system illustratedin FIG. 1.

FIG. 4 is a perspective view from the underside of a pivot hoodillustrated in FIG. 2.

FIG. 5 is a sectional view of the pivot hood assembly illustrated inFIG. 2 taken along view line 5-5.

FIG. 6 is a side elevational view of the hooded ventilation systemillustrated in FIG. 1 showing the pivot hoods in a closed configuration.

FIG. 7 is a side elevational view of the hooded ventilation systemillustrated in FIG. 1 showing the pivot hoods in an open configuration.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

With reference to the Figures, and specifically to FIG. 1, a hoodedventilation system 10 according to the invention is illustratedcomprising a pivot hood assembly 12 operably attached to a well-knownventilation shaft 18. The ventilation shaft 18 can be provided with amotorized fan assembly (not shown) installed in the interior of theventilation shaft 18 to facilitate the movement of air through theventilation shaft 18.

The pivot hood assembly 12 comprises a pair of identical hoods 14, 16.Each hood 14, 16 comprises a generally rectilinear shell 20, 22,respectively, supported by a rectilinear frame assembly 24, 26,respectively, to form a unitary hood structure. The hoods 14, 16 areattached to the ventilation shaft 18 through a pair of parallelattachment members 28, 30, thereby forming an attachment framework 32.

Referring now to FIGS. 2-4, the shell 20 of the hood 14 comprises aplanar top wall 40, and a pair of planar, parallel side walls 42, 44depending orthogonally therefrom along a lateral edge thereof. A planarinclined wall 46 inclines downwardly from the top wall 40, and connectsthe side walls 42, 44. A planar outer wall 48 extends downwardly fromthe inclined wall 46, orthogonal to the top wall 40 and connecting theside walls 42, 44. The top wall 40 and side walls 42, 44 terminate inand define a rectilinear inner edge 52. The shell 20 defines an airflowchamber 50. The top wall 40, side walls 42, 44, inclined wall 46, andouter wall 48 are interconnected in a suitable manner, such as bywelding. The walls 40-48 are fabricated of a suitable material ofsufficient strength and durability for the purposes described herein,such as aluminum or steel.

The shell 22 of the hood 16 comprises a planar top wall 60, and a pairof planar, parallel side walls 62, 64 depending orthogonally therefromalong a lateral edge thereof. A planar inclined wall 66 inclinesdownwardly from the top wall 60, and connects the side walls 62, 64. Aplanar outer wall 68 extends downwardly from the inclined wall 66,orthogonal to the top wall 60 and connecting the side walls 62, 64. Thetop wall 60 and side walls 62, 64 terminate in and define a rectilinearinner edge 72. The shell 22 defines an airflow chamber 70. The top wall60, side walls 62, 64, inclined wall 66, and outer wall 68 areinterconnected in a suitable manner, such as by welding. The walls 60-68are fabricated of a suitable material of sufficient strength anddurability for the purposes described herein, such as aluminum or steel.

Referring also to FIG. 5, the frame assembly 24 comprises a parallelarray of equal length members, including a pair of outer longitudinalframe member 80, 86, and a pair of inner longitudinal frame members 82,84. The outer longitudinal frame member 80 extends along a lower edge ofthe side wall 42. The outer longitudinal frame member 86 extends along alower edge of the side wall 44. The members 80-86 are joinedorthogonally along one end by an outer lateral frame member 92 extendingalong a lower edge of the outer wall 48. An intermediate lateral framemember 90 and an inner lateral frame member 88 extend orthogonallybetween the inner longitudinal frame members 82, 84. An end lateralframe member 94 extends between the outer longitudinal frame member 80and the inner longitudinal frame member 82 opposite the outer lateralframe member 92, and an end lateral frame member 96 extends between theouter longitudinal frame member 86 and the inner longitudinal framemember 84 opposite the outer lateral frame member 92.

The outer longitudinal frame member 80, inner longitudinal frame member82, the end lateral frame member 94 and the outer lateral frame member92 comprise a rectilinear frame defining a lateral opening 98.Similarly, the outer longitudinal frame member 86, inner longitudinalframe member 84, the end lateral frame member 96 and the outer lateralframe member 92 comprise a rectilinear frame defining a lateral opening100. The inner lateral frame member 88, the inner longitudinal framemembers 82, 84, and the outer lateral frame member 92 comprise arectilinear frame defining an end opening 102. The inner longitudinalframe members 82, 84 and the inner lateral frame member 88 are adaptedto closely abut the perimeter of the ventilation shaft 18.

The frame assembly 26 comprises a parallel array of equal lengthmembers, including a pair of outer longitudinal frame members 110, 116,and a pair of inner longitudinal frame members 112, 114. The outerlongitudinal frame member 110 extends along a lower edge of the sidewall62. The outer longitudinal frame member 116 extends along a lower edgeof the sidewall 64. The members 110-116 are joined orthogonally alongone end by an outer lateral frame member 122 extending along a loweredge of the outer wall 68. An intermediate lateral frame member 120 andan inner lateral frame member 118 extend orthogonally between the innerlongitudinal frame members 112, 114. An end lateral frame member 124extends between the outer longitudinal frame member 110 and the innerlongitudinal frame member 112 opposite the outer lateral frame member122, and an end lateral frame member 126 extends between the outerlongitudinal frame member 116 and the inner longitudinal frame member114 opposite the outer lateral frame member 122.

The outer longitudinal frame member 110, inner longitudinal frame member112, the end lateral frame member 124 and the outer lateral frame member122 comprise a rectilinear frame defining a lateral opening 128.Similarly, the outer longitudinal frame member 116, inner longitudinalframe member 114, the end lateral frame member 126 and the outer lateralframe member 122 comprise a rectilinear frame defining a lateral opening130. The inner lateral frame member 118, the inner longitudinal framemembers 112, 114, and the outer lateral frame member 122 comprise arectilinear frame defining an end opening 132. The inner longitudinalframe members 112, 114 and the inner lateral frame member 118 areadapted to closely abut the perimeter of the ventilation shaft 18.

The attachment members 28, 30 are elongated members adapted to beattached along an upper edge of the ventilation shaft 18 and to extendlaterally beyond the edges of the ventilation shaft 18. The attachmentmembers 28, 30 can comprise solid or hollow metal bars, such as steelbars or square tubing, having suitable strength and rigidity for thepurposes described herein. Each end of the members 28, 30 is adapted toform a pivot connection for pivotably connecting a pivot hood 14, 16thereto. As illustrated in FIGS. 2 and 5, the attachment member 28 isjoined at a first end to the inner longitudinal frame member 84 througha pivot connection 144, and at a second end to the inner longitudinalframe member 114 through a pivot connection 146. Similarly, theattachment member 30 is joined at a first end to the inner longitudinalframe member 82 through a pivot connection 140, and at a second end tothe inner longitudinal frame member 112 through a pivot connection 142.The pivot connections enable the pivot hoods 12, 14 to pivot upwardlyand outwardly away from the ventilation shaft 18. The position of thepivot connections is selected so that the hoods 12, 14 are balanced toenable a person to readily lift and lower the hoods 12, 14.

The attachment members 28, 30 are attached to the ventilation shaft 18,as illustrated in FIG. 2, through suitable fasteners extending throughthe attachment members 28, 30 into the walls of the ventilation shaft18. Preferably, the attachment members 28, 30 are attached to theventilation shaft 18 at an upper portion thereof adjacent theventilation shaft opening so that, when the pivot hood assembly 12 is ina closed configuration, the bottom of the pivot hood assembly 12 willextend somewhat below the end of the ventilation shaft 18.

FIG. 6 illustrates the hooded ventilation system 10 with the pivot hoodassembly 12 in a closed configuration. In the closed position, the inneredges 52, 72 will be brought into contact with each other. The pivothoods 14, 16 can be provided with suitable closure devices, such astoggle latches (not shown), to maintain the pivot hoods 14, 16 in theclosed configuration. Air can flow to or from the ventilation shaft 18through the lateral openings 98, 100, 128, 130 and the end openings 102,132 along the perimeter of the pivot hood assembly 12 and theventilation shaft 18. FIG. 7 illustrates the hooded ventilation system10 with the pivot hood assembly 12 in an open configuration. In thisconfiguration, the pivot hoods 14, 16 have been pivoted upwardly andoutwardly away from each other, thereby enabling ready access to theventilation shaft 18.

If the pivot hood assembly 12 is used with an air inlet shaft,conventional air filters can be installed in the pivot hoods 14, 16 tofilter the air entering the ventilation shaft 18. The filters (notshown) can be single use, fiber-type filters, electrostaticprecipitation filters, and the like. The filters would be installed inthe frame assemblies 24, 26 in the lateral openings 98, 100, 128, 130and the end openings 102, 132 to completely intercept air entering thepivot hoods 14, 16. If the pivot hood assembly 12 is used with an airexhaust shaft, conventional air filters can be eliminated. However,screening elements (not shown) can be inserted in the lateral openings98, 100, 128, 130 and the end openings 102, 132 to prevent the intrusionof animals into the pivot assembly 12 and the ventilation shaft 18. Withboth the air filters and screening elements, the frame assemblies 24, 26can be adapted with suitable members and retainers for supporting and aretaining the air filters and screening elements in the lateral openings98, 100, 128, 130 and the end openings 102, 132.

The pivot hood assembly 12 has been described herein as a manuallyoperable assembly, i.e. the pivot hoods 14, 16 are opened and closedmanually. However, in an alternate embodiment, a motorized liftmechanism can be employed to raise and lower the pivot hoods 14, 16. Itis anticipated that the lift mechanism would comprise a generallyconventional motor, preferably electrically-powered, gearing, structuralmembers, and the like, in a configuration recognizable to a person ofordinary skill in the art as suitable for raising and lowering the pivothoods 14, 16.

In a further embodiment, the pivot hoods 14, 16 can be cooperativelylinked so that the raising or lowering of one pivot hood will raise orlower the other pivot hood. A suitable linkage connecting the two pivothoods would be utilized to facilitate the coordinated movement of bothpivot hoods.

The pivot hood assembly described herein comprising two identical,mating pivot hoods enables a single person to pivot the pivot hoodassembly away from a ventilation shaft in order to gain access to theshaft. Complete unobstructed access to the interior of the ventilationshaft is enabled by the use of the two pivot hoods which can beseparated and positioned at opposite ends of the shaft, therebyfacilitating access to a motorized fan assembly installed in the shaft.The installation of the pivot hood assembly to the ventilation shaft isalso facilitated because of the ability to separately mount the twopivot hoods, each of which weighs significantly less than a conventionalhood assembly. Finally, transportation of the pivot hood assembly isfacilitated by the ability to ship the hood assembly in two parts ratherthan as a single unit having twice the weight and size as each pivothood.

While the invention has been specifically described in connection withcertain specific embodiments thereof, it is to be understood that thisis b y way of illustration and not of limitation. Reasonable variationand modification are possible within the scope of the forgoingdisclosure and drawings without departing from the spirit of theinvention which is defined in the appended claims.

1. A pivot hood assembly (12) for a ventilation shaft (18), comprising:a pair of hood pieces (14, 16), each hood piece comprising a shell (20,22) having an inner edge (52), and a supporting frame assembly (24, 26);and an attachment framework (32) adapted to be securely fixed to theventilation shaft (18), each hood piece (14, 16) being pivotably mountedto the attachment framework (32) for movement between a closed positionwhere the inner edges (52) contact each other and an open position wherethe inner edges (52) are spaced from each other to form an opening;whereby when the attachment framework (32) is fixed to the ventilationshaft (18) and the hood pieces (14, 16) are pivoted to the closedposition, the pivot hood assembly (12) is configured to control the flowof air entering or exiting the ventilation shaft (18), and when the hoodpieces (14, 16) are pivoted to the open position, the ventilation shaft(18) is accessible through the opening.
 2. The pivot hood assembly (12)of claim 1 wherein each hood piece (14, 16) is pivotably mounted to theattachment framework (32) at a balanced pivot point wherein little forceis required to urge the hood piece to pivot.
 3. The pivot hood assembly(12) of claims 1 or 2 further comprising at least one closure device tosecure the inner edges (52) to each other when the hood pieces (14, 16)are in the closed position.
 4. The pivot hood assembly (12) of any ofclaims 1-3 wherein the hood pieces (14, 16) are cooperatively linked sothat movement of one hood piece will also move the other hood piece. 5.The pivot hood assembly (12) of any of claims 1-4 further comprising atleast one motor to move the pivot hoods between the open and closedpositions.
 6. The pivot hood assembly (12) of any of claims 1-5 furthercomprising an air filter in each pivot hood.
 7. The pivot hood assembly(12) of any of claims 1-6 further comprising a screen in each pivothood.
 8. The pivot hood assembly (12) of any of claims 1-7 mounted tothe ventilation shaft (18) with the attachment framework (32) attachedto the ventilation shaft at an upper end thereof so that when the hoodpieces (14, 16) are in the closed position, the pivot hood assembly (12)has a portion extending below the ventilation shaft end.